Anticipated Impacts on Veterans Healthcare - The proposed study has the potential to improve the quality of VA healthcare by establishing the effectiveness of a Posttraumatic Stress Disorder (PTSD) intervention for Veterans treated in VA primary care: Clinician-Supported PTSD Coach (CS PTSD Coach). This proposal will contribute to improving the mental health of primary care patients with PTSD by teaching coping skills to manage PTSD symptoms and increasing their engagement in specialty mental health (MH) services. The long- term goal of this program is to establish effective, innovative, and easily disseminated mobile health interventions to improve the quality of healthcare for Veterans with PTSD presenting in VA primary care. Background - PTSD is highly prevalent in Veterans seen in VA primary care; however, there is a lack of evidence-based brief PTSD interventions that can be delivered in this setting. Therefore, Veterans with PTSD are offered referrals to specialty MH care where evidence-based psychotherapies are available. Unfortunately, many patients refuse such referrals or if accepted, infrequently attend enough sessions to receive adequate treatment. Consequently, a significant gap exists between need for and engagement in effective PTSD treatment for Veterans seen exclusively in VA primary care. Innovative technology could help address this need by increasing access to and quality of PTSD treatment. VA's National Center for PTSD has developed PTSD Coach, an evidence-informed self-management mobile app that offers PTSD psycho-education, symptom monitoring, coping skills, and links to social support and professional resources. While, substantial evidence exists that technology-based self-management programs for MH conditions are effective, self- management programs when used alone are often underutilized. Interventions that include clinician support increase treatment utilization and effectiveness. Therefore, we have developed a treatment package that combines mobile technology with clinician support. Pilot data indicate participation in CS PTSD Coach leads to clinically significant reductions in PTSD symptoms and increased engagement in specialty MH care. Objectives - The primary objective of this research is to conduct a randomized controlled trial (RCT) of Clinician-Supported PTSD Coach in VA primary care with Veterans with clinically significant PTSD symptoms. The specific aims are to 1) investigate the impact of CS PTSD Coach on PTSD symptom severity, 2) investigate the impact of CS PTSD Coach on engagement in two sessions of specialty mental health care, and 3) investigate patient and provider satisfaction with CS PTSD Coach. We also aim to explore potential mediators (i.e., objective app use, coping self-efficacy) and moderators (i.e., baseline PTSD symptom severity, comorbid psychiatric symptoms) of outcomes. We will also explore trajectories of PTSD symptom change over the four month follow-up period to examine if engagement in specialty MH treatment and continued app use interact with symptom change. Research Design and Methods - This is a four-year, two-site, two-arm RCT that will compare CS PTSD Coach to a standard referral to a Primary Care Mental Health Integration (PC-MHI) provider. CS PTSD Coach consists of four 20-30 minute sessions (in-person or via phone) over eight weeks focused on instructions for app use, setting symptom reductions goals, and assigning specific PTSD Coach activities (e.g., assessments, management strategies, psycho-educational readings) for the participant to complete between sessions. Participants will be VA primary care patients with clinically significant PTSD symptoms (N = 260). Assessments will include well-established clinical interviews and self-report measures that will take place at pre-treatment (baseline), post-treatment, and at 16- and 24-week follow-up. The study will also use VHA administrative data to assess MH treatment engagement, objective app usage data to assess app use, and qualitative methodology to assess CS PTSD Coach participant satisfaction.